"Accidentally. I walked in on him and he threw me out. He was savage. He's usually good-natured enough, and I consider it a bad sign that he was so upset at the intrusion. But the fact remains that he was telling a joke to Multivac, and I'm convinced it was one of a series."

"But why?"

Whistler shrugged and rubbed a hand fiercely across his chin. "I have thought about that. I think he's trying to build up a store of jokes in Multivac's memory banks in order to get back new variations. You see what I mean? He's planning a mechanical jokester, so that he can have an infinite number of jokes at hand and never fear running out."